1. Field of Invention
The present invention relates to a vehicle control system and a recording medium recorded with programs for the system.
2. Description of Related Art
In a vehicle of the prior art having a navigation system mounted thereon, a guide route is calculated on the basis of the present position of the vehicle, as recognized by the navigation system, and a target set by the driver, so that the vehicle can be driven according to the guide route calculated. When the vehicle approaches a corner, a corner control is made so that the vehicle can turn around the corner at a lower speed gear stage. For this cornering, there is arranged a vehicle control system which calculates a recommended vehicle speed optimum for turning the corner on the basis of road data read out from data files and the present position detected by present position detecting means. Moreover, the vehicle control system compares the recommended vehicle speed and the present vehicle speed to issue a deceleration command, when the present position exceeds the recommended vehicle speed, thereby effect a downshift at the time of a predetermined operation, such as when the driver releases the accelerator or applies the brakes.
When there occurs errors between actual road structures and conditions and the road data stored in the road files, such as detection errors by present position detecting means or logical errors, the present position may not be accurately recognized.
Therefore, the vehicle control system recognizes that the guide route is missed, when a deviation between the recognized present position and the guide route becomes large, to inhibit the corner control.
In the vehicle control system of the related art, however, the corner control is effected for a small deviation. As a result, the position or timing for a downshift may become so different, as estimated from the actual road situations, as to give the driver a feeling of physical disorder.